(1) Field of the Invention
The present invention relates to a ceramic leadless package usable for mounting a small size electronic device such as a semiconductor or the like and connecting it to a circuit substrate. And also, the invention relates to a process for manufacturing such a ceramic leadless package.
(2) Description of the Prior Art
As the ceramic package of this type, there have hitherto been employed a laminated type chip carrier and a flat type chip carrier, but they have the following drawbacks: (1) When the top surface of the package is flat, for instance, as in the package described in U.S. Pat. No. 3,404,214, external terminals provided on the top surface of the package are substantially flush with the top surface of the package, so that it is necessary to separate these adjacent terminals from each other by grooves. If there is no groove, when the external terminals or the top surface of the package is soldered to another substrate, short circuit is apt to occur between the terminals due to the bridging of the solder.
(2) When the package is not provided on its side surface and bottom surface with connection conductors as in the abovementioned package, if the top surface of such a package is connected to another circuit substrate, the soldering for terminals cannot sufficiently be confirmed from the exterior and the soldered area is small, so that the adhesive strength becomes insufficient.
(3) When the package surface is flat as in the laminated type chip carrier or the flat type chip carrier, there remains substantially no space between the package surface and another circuit substrate after the package is connected to the circuit substrate, and hence electronic components cannot be attached to the mounting area occupied in the package, so that the packaging density for the circuit substrate is restricted. Moreover, since there is a limit on the connecting area between the top surface of the package and the circuit substrate, the heat dissipation is not achieved sufficiently.
(4) As disclosed in U.S. Pat. No. 3,483,308 (Japanese Patent Application Publication No. 49-41,901), there is proposed a supporting member for an electronic device, which is produced by subjecting a flat ceramic carrier body provided on its bottom surface with projections to a metallization. In this type of the package, conductors extending over the respective projections are formed after the molding or firing of the ceramic body, so that the mass-productivity is poor, and it is difficult to make the body lighter and thinner.